bitops.h

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

#ifndef _M68K_BITOPS_H
#define _M68K_BITOPS_H
/*
 * Copyright 1992, Linus Torvalds.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

/*
 * Require 68020 or better.
 *
 * They use the standard big-endian m680x0 bit ordering.
 */

#define test_and_set_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_test_and_set_bit(nr, vaddr) : \
   __generic_test_and_set_bit(nr, vaddr))

extern __inline__ int __constant_test_and_set_bit(int nr,volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bset %2,%1; sne %0"
	     : "=d" (retval), "+m" (((volatile char *)vaddr)[(nr^31) >> 3])
	     : "di" (nr & 7));

	return retval;
}

extern __inline__ int __generic_test_and_set_bit(int nr,volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfset %2@{%1:#1}; sne %0"
	     : "=d" (retval) : "d" (nr^31), "a" (vaddr) : "memory");

	return retval;
}

#define set_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_set_bit(nr, vaddr) : \
   __generic_set_bit(nr, vaddr))

#define __set_bit(nr,vaddr) set_bit(nr,vaddr) 

extern __inline__ void __constant_set_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bset %1,%0"
	     : "+m" (((volatile char *)vaddr)[(nr^31) >> 3]) : "di" (nr & 7));
}

extern __inline__ void __generic_set_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bfset %1@{%0:#1}"
	     : : "d" (nr^31), "a" (vaddr) : "memory");
}

#define test_and_clear_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_test_and_clear_bit(nr, vaddr) : \
   __generic_test_and_clear_bit(nr, vaddr))

#define __test_and_clear_bit(nr,vaddr) test_and_clear_bit(nr,vaddr)

extern __inline__ int __constant_test_and_clear_bit(int nr, volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bclr %2,%1; sne %0"
	     : "=d" (retval), "+m" (((volatile char *)vaddr)[(nr^31) >> 3])
	     : "di" (nr & 7));

	return retval;
}

extern __inline__ int __generic_test_and_clear_bit(int nr, volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfclr %2@{%1:#1}; sne %0"
	     : "=d" (retval) : "d" (nr^31), "a" (vaddr) : "memory");

	return retval;
}

/*
 * clear_bit() doesn't provide any barrier for the compiler.
 */
#define smp_mb__before_clear_bit()	barrier()
#define smp_mb__after_clear_bit()	barrier()

#define clear_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_clear_bit(nr, vaddr) : \
   __generic_clear_bit(nr, vaddr))

extern __inline__ void __constant_clear_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bclr %1,%0"
	     : "+m" (((volatile char *)vaddr)[(nr^31) >> 3]) : "di" (nr & 7));
}

extern __inline__ void __generic_clear_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bfclr %1@{%0:#1}"
	     : : "d" (nr^31), "a" (vaddr) : "memory");
}

#define test_and_change_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_test_and_change_bit(nr, vaddr) : \
   __generic_test_and_change_bit(nr, vaddr))

#define __test_and_change_bit(nr,vaddr) test_and_change_bit(nr,vaddr)
#define __change_bit(nr,vaddr) change_bit(nr,vaddr)

extern __inline__ int __constant_test_and_change_bit(int nr, volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bchg %2,%1; sne %0"
	     : "=d" (retval), "+m" (((volatile char *)vaddr)[(nr^31) >> 3])
	     : "di" (nr & 7));

	return retval;
}

extern __inline__ int __generic_test_and_change_bit(int nr, volatile void * vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfchg %2@{%1:#1}; sne %0"
	     : "=d" (retval) : "d" (nr^31), "a" (vaddr) : "memory");

	return retval;
}

#define change_bit(nr,vaddr) \
  (__builtin_constant_p(nr) ? \
   __constant_change_bit(nr, vaddr) : \
   __generic_change_bit(nr, vaddr))

extern __inline__ void __constant_change_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bchg %1,%0"
	     : "+m" (((volatile char *)vaddr)[(nr^31) >> 3]) : "di" (nr & 7));
}

extern __inline__ void __generic_change_bit(int nr, volatile void * vaddr)
{
	__asm__ __volatile__ ("bfchg %1@{%0:#1}"
	     : : "d" (nr^31), "a" (vaddr) : "memory");
}

extern __inline__ int test_bit(int nr, const volatile void * vaddr)
{
	return ((1UL << (nr & 31)) & (((const volatile unsigned int *) vaddr)[nr >> 5])) != 0;
}

extern __inline__ int find_first_zero_bit(void * vaddr, unsigned size)
{
	unsigned long *p = vaddr, *addr = vaddr;
	unsigned long allones = ~0UL;
	int res;
	unsigned long num;

	if (!size)
		return 0;

	size = (size >> 5) + ((size & 31) > 0);
	while (*p++ == allones)
	{
		if (--size == 0)
			return (p - addr) << 5;
	}

	num = ~*--p;
	__asm__ __volatile__ ("bfffo %1{#0,#0},%0"
			      : "=d" (res) : "d" (num & -num));
	return ((p - addr) << 5) + (res ^ 31);
}

extern __inline__ int find_next_zero_bit (void *vaddr, int size,
				      int offset)
{
	unsigned long *addr = vaddr;
	unsigned long *p = addr + (offset >> 5);
	int set = 0, bit = offset & 31UL, res;

	if (offset >= size)
		return size;

	if (bit) {
		unsigned long num = ~*p & (~0UL << bit);

		/* Look for zero in first longword */
		__asm__ __volatile__ ("bfffo %1{#0,#0},%0"
				      : "=d" (res) : "d" (num & -num));
		if (res < 32)
			return (offset & ~31UL) + (res ^ 31);
                set = 32 - bit;
		p++;
	}
	/* No zero yet, search remaining full bytes for a zero */
	res = find_first_zero_bit (p, size - 32 * (p - addr));
	return (offset + set + res);
}

/*
 * ffz = Find First Zero in word. Undefined if no zero exists,
 * so code should check against ~0UL first..
 */
extern __inline__ unsigned long ffz(unsigned long word)
{
	int res;

	__asm__ __volatile__ ("bfffo %1{#0,#0},%0"
			      : "=d" (res) : "d" (~word & -~word));
	return res ^ 31;
}

#ifdef __KERNEL__

/*
 * ffs: find first bit set. This is defined the same way as
 * the libc and compiler builtin ffs routines, therefore
 * differs in spirit from the above ffz (man ffs).
 */

extern __inline__ int ffs(int x)
{
	int cnt;

	__asm__ __volatile__("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));

	return 32 - cnt;
}

/*
 * hweightN: returns the hamming weight (i.e. the number
 * of bits set) of a N-bit word
 */

#define hweight32(x) generic_hweight32(x)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)

/* Bitmap functions for the minix filesystem */

extern __inline__ int
minix_find_first_zero_bit (const void *vaddr, unsigned size)
{
	const unsigned short *p = vaddr, *addr = vaddr;
	int res;
	unsigned short num;

	if (!size)
		return 0;

	size = (size >> 4) + ((size & 15) > 0);
	while (*p++ == 0xffff)
	{
		if (--size == 0)
			return (p - addr) << 4;
	}

	num = ~*--p;
	__asm__ __volatile__ ("bfffo %1{#16,#16},%0"
			      : "=d" (res) : "d" (num & -num));
	return ((p - addr) << 4) + (res ^ 31);
}

extern __inline__ int
minix_test_and_set_bit (int nr, volatile void *vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfset %2{%1:#1}; sne %0"
	     : "=d" (retval) : "d" (nr^15), "m" (*(volatile char *)vaddr) : "memory");

	return retval;
}

#define minix_set_bit(nr,addr)	((void)minix_test_and_set_bit(nr,addr))

extern __inline__ int
minix_test_and_clear_bit (int nr, volatile void *vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfclr %2{%1:#1}; sne %0"
	     : "=d" (retval) : "d" (nr^15), "m" (*(volatile char *) vaddr) : "memory");

	return retval;
}

extern __inline__ int
minix_test_bit (int nr, const volatile void *vaddr)
{
	return ((1U << (nr & 15)) & (((const volatile unsigned short *) vaddr)[nr >> 4])) != 0;
}

/* Bitmap functions for the ext2 filesystem. */

extern __inline__ int
ext2_set_bit (int nr, volatile void *vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfset %2{%1,#1}; sne %0"
	     : "=d" (retval) : "d" (nr^7), "m" (*(volatile char *) vaddr) : "memory");

	return retval;
}

extern __inline__ int
ext2_clear_bit (int nr, volatile void *vaddr)
{
	char retval;

	__asm__ __volatile__ ("bfclr %2{%1,#1}; sne %0"
	     : "=d" (retval) : "d" (nr^7), "m" (*(volatile char *) vaddr) : "memory");

	return retval;
}

extern __inline__ int
ext2_test_bit (int nr, const volatile void *vaddr)
{
	return ((1U << (nr & 7)) & (((const volatile unsigned char *) vaddr)[nr >> 3])) != 0;
}

extern __inline__ int
ext2_find_first_zero_bit (const void *vaddr, unsigned size)
{
	const unsigned long *p = vaddr, *addr = vaddr;
	int res;

	if (!size)
		return 0;

	size = (size >> 5) + ((size & 31) > 0);
	while (*p++ == ~0UL)
	{
		if (--size == 0)
			return (p - addr) << 5;
	}

	--p;
	for (res = 0; res < 32; res++)
		if (!ext2_test_bit (res, p))
			break;
	return (p - addr) * 32 + res;
}

extern __inline__ int
ext2_find_next_zero_bit (const void *vaddr, unsigned size, unsigned offset)
{
	const unsigned long *addr = vaddr;
	const unsigned long *p = addr + (offset >> 5);
	int bit = offset & 31UL, res;

	if (offset >= size)
		return size;

	if (bit) {
		/* Look for zero in first longword */
		for (res = bit; res < 32; res++)
			if (!ext2_test_bit (res, p))
				return (p - addr) * 32 + res;
		p++;
	}
	/* No zero yet, search remaining full bytes for a zero */
	res = ext2_find_first_zero_bit (p, size - 32 * (p - addr));
	return (p - addr) * 32 + res;
}

#endif /* __KERNEL__ */

#endif /* _M68K_BITOPS_H */